taxpayers, boston only, don't worry if you missed the tax filing deadline last night. they'll give extensions, and they plan to talk more about how that will be done later today. richard? >> traci potts, thank you so much. >>> people at the scene of the explosions are speaking about what they saw. one witness saying he could feel the explosions from his feet to his chest. a photographer on the scene shared his story with our own brian williams. he was just half a block away when he heard the first explosion. >> it was one of the craziest scenes i've ever scene. everyone was rushing. no one knew what to do. most of the people were running away. you know, the ems was running towards the scene. nobody knew what to do or what was happening. everyone was just in fear. >> this is like a bomb explosion that we hear about in the news in baghdad or israel or some other tragic place in the world. >> it went off and me and him -- we're rooting on our friend and like oh, yeah. and then it was, like, boom! both of us, we've been to afghanistan. you expect that there. i didn't expect that here.